A tremor is a medical condition characterized by involuntary, and somewhat continuous, muscle contractions and relaxations. It is one of the most common involuntary movements and can affect the head, face, eyes, arms, hands, vocal folds, trunk, and legs. Tremors are often symptomatic of a neurological disorder.
Tremor is sometimes associated with damage to the parts of the brain that control the shaking muscles. Conditions that can cause tremor include stroke, multiple sclerosis, brain injury, chronic kidney disease, and Parkinson's disease. There are several different categories of tremor. Resting tremors are worse at rest and commonly result from Parkinson's disease. Contraction tremors are worse during muscle contraction. Posture tremors are worse when the patient maintains a posture against gravity. And intention tremors are tremors that worsen during intention (for example, as a patent's finger nears a target).
While tremor can be managed though lifestyle changes (e.g., eliminating tremor “triggers” like caffeine and other stimulants, attending physical therapy, etc.), there is often no cure for tremor. Furthermore, daily activities are still complicated by the tremor even with management. For example, activities requiring small precise movements can be difficult or impossible as a result of the constant shaking.